ABSTRACT
BACKGROUND AND AIM: The role of dietary protein and glycemic index on insulin resistance (based on TyG index) within a nutritional program for weight loss and weight maintenance was examined. METHODS: This study analyzed 744 adults with overweight/obesity within the DIOGenes project. Patients who lost at least 8% of their initial weight (0-8 weeks) after a low-calorie diet (LCD) were randomly assigned to one of five ad libitum diets designed for weight maintenance (8-34 weeks): high/low protein (HP/LP) and high/low glycemic index (HGI/LGI), plus a control. The complete nutritional program (0-34 weeks) included both LCD plus the randomized diets intervention. The TyG index was tested as marker of body mass composition and insulin resistance. RESULTS: In comparison with the LP/HGI diet, the HP/LGI diet induced a greater BMI loss (p < 0.05). ∆TyG was positively associated with resistance to BMI loss (ß = 0.343, p = 0.042) during the weight maintenance stage. In patients who followed the HP/LGI diet, TyG (after LCD) correlated with greater BMI loss in the 8-34 weeks period (r = -0.256; p < 0.05) and during the 0-34 weeks intervention (r = -0.222, p < 0.05) periods. ΔTyG1 value was associated with ΔBMI2 (ß = 0.932; p = 0.045) concerning the HP/LGI diet. CONCLUSIONS: A HP/LGI diet is beneficial not only for weight maintenance after a LCD, but is also related to IR amelioration as assessed by TyG index changes. Registration Clinical Trials NCT00390637.
ABSTRACT
BACKGROUND: This study aimed to investigate the putative role of the triglyceride-glucose index (TyG index) computed as ln[TG (mg/dl) × glucose (mg/dl)/2] and derived proxies as predictors of adiposity and weight loss changes after a low-calorie diet (LCD) intervention. METHODS: A total of 744 adult participants from the multicentre DIOGenes intervention study were prescribed a LCD (800 kcal/day) during 8 weeks. Body composition and fat content at baseline and after 8 weeks were estimated by DEXA/BIA. A multivariate analysis approach was used to estimate the difference in ΔWeight1-2 (kg), ΔBMI1-2 (kg/m2 ) or ΔFat1-2 (%) between the basal value (point 1) and after 8 weeks following a LCD (point 2), respectively. The TyG index at baseline (TyG1 ), after following the LCD for 8 weeks (TyG2 ) or the TyG index differences between both time points (ΔTyG1-2 ) were analysed as predictors of weight and fat changes. RESULTS: TyG1 was associated with ΔWeight1-2 (kg) and ΔBMI1-2 (kg/m2 ), with ß = 0.812 (p = .017) and ß = 0.265 (p = .018), respectively. Also, TyG2 values were inversely related to ΔFat1-2 (%), ß = -1.473 (p = .015). Moreover, ΔTyG1-2 was associated with ΔWeight1-2 (kg) and ΔFat1-2 (%), ß = 0.689 (p = .045) and ß = 1.764 (p = .002), respectively. Furthermore, an association between TyG2 and resistance to fat loss was found (p = .015). CONCLUSION: TyG1 index is a good predictor of weight loss induced by LCD. Moreover, TyG2 was closely related to resistance to fat loss, while ΔTyG1-2 values were positively associated with body fat changes. Therefore, TyG index and derived estimations could be used as markers of individualized responses to energy restriction and a surrogate of body composition outcomes in clinical/epidemiological settings in obesity conditions.
